The Natural Color System (NCS) is the color standard (for interior design, decorating, and painting) in Sweden, Spain, Norway and South Africa. The NCS standard is unique because it is based entirely on the perception of colors (how eyes naturally see red, yellow, blue, green, white, and black). NCS does not use color names. It uses letters and numbers to describe any color. NCS colors cannot be used directly in HTML, because HTML processes color values differently. However, the numeric values of NCS can be used to compute "look alike" HTML colors. The #hex values are non official approximate values intended to simulate NCS colors in HTML.More details https://ncscolour.com/ncs/